Grout Line Size

Spacing Is Not Uniform

• There is no uniform spacing for tile grout lines. Much is personal preference, what the homeowner or installer thinks looks best. As a general rule, larger tiles have larger grout spaces. Smaller tiles, such as those used on kitchen counters, bathroom walls and showers, usually have smaller spaces, because those tiles are made with edges designed to fit close to each other.

Some Tiles Are Self-spacing

• Small tiles, such as the 4-inch by 4-inch style commonly used on bathroom and kitchen walls, often are self-spacing. They have small protrusions called lugs that fit against adjoining tiles and create an automatic space for grout, normally 1/32 to 1/16 inch wide. Grout lines on walls usually do not exceed 1/16 inch because the tiles need to be stacked to help support them during installation.

Floor Tiles Need Larger Lines

• As a general rule, floor tiles should have grout lines of 1/8 inch or larger, depending on the type and size of tile; most floor tiles are 8 inches by 8 inches, but larger versions are available. Special types, such as slate or quarry tiles, often do not have edges uniform enough to look good with tight spacing. These tiles usually are spaced with grout lines 3/16 inch or wider. Some clay or quarry tiles are installed with 1/4-inch grout gaps, or are even wider in some installations. Plastic spacers are usually used at tile corners to form even grout spaces.

Measure for Floor Lines

• One way to determine a good grout line on a floor is to lay nine tiles in a square and measure corner to corner in both directions. If those measurements are within 1/16 inch, you can go that small with a grout line. Some really large-format tiles, 18 by 18 inches square or larger, look good with very narrow grout lines that are filled with a grout colored to match the tile. This technique produces a floor that looks like a single slab.

Sanded vs. Unsanded Grout

• Use unsanded grout on small lines, sanded on larger spacings. The sand helps bond the grout and gives it more strength. Floor tiles almost always use sanded grout. The unsanded version is easier to force into the smaller spaces on wall tiles. Epoxy grout is harder to work with and does not work with some types of stone tiles, but it is more durable and less subject to staining.